perceptual modalities

Marek McGann

Perceptual ModalitiesModes of Presentation or Modes of Interaction?

Abstract: Perceptual modalities have been traditionally considered

the product of dedicated biological systems producing information for

higher cognitive processing. Psychological and neuropsychological

evidence is offered which undermines this point of view and an alter-

native account of modality from the enactive approach to understand-

ing cognition is suggested. Under this view, a perceptual modality is a

stable form of perception which is structured not just by the biological

sensitivities of the agent, but by their goals and the set of skills or

expertise which they are deploying at a given time. Such a view sug-

gests that there is no such thing as an experience that is purely visual,

auditory, or otherwise modal and that our attempts to understand

consciousness and the mind must be conducted within a framework

that provides an account of embodied, goal-directed adaptive coping

with the world.

Keywords: Modality, perception, sensation, enaction, skill theory,

consciousness

Introduction

This paper is about perceptual modalities — how we should conceive

of them and what their relationship is to our bodies and to our

consciousnesses. Addressing such a topic, however, first demands

that we get straight a common distinction between ‘sensation’ on the

one hand, and ‘perception’ on the other.

Cognitive scientists tend to interpret the distinction between sensa-

tion and perception in one of two ways. The first makes a strong

Journal of Consciousness Studies, 17, No. 1–2, 2010, pp. 72–94

Correspondence:Marek McGann, Department of Psychology, Mary Immaculate College, Univer-sity of Limerick. Email: [email protected]

distinction between the two, making the former a physiological pro-

cess and the latter a psychological one. In this case, sensation is a

characteristic of various surfaces and cells of the body which react in

particular ways when they make contact with particular forms of

energy such as light, pressure, or sound, or with certain chemicals.

Perception, on this strong view, is the psychological process, enabled

by sensation, by which we come to some form of direct knowledge of

the world.

The second form of the sensation-perception distinction found

amongst cognitive scientists makes the division between the two less

clear. In this case, sensation is the bare basis of later perception, the

recognition of elementary aspects of a given object or stimulus such as

its form, colour or pitch. Perception, then, is the process by which

these elements are assembled or bound into coherent but complex

wholes, transforming the sensations of redness and roundness into the

perception of a ripe tomato, for instance. This second form of the dis-

tinction, though both popular and quite intuitive, begs for confusion.

The physiological aspects of sensation are less clearly articulated,

though generally remaining at the foundation of such basic aspects of

perception as recognition of colour and form. In this second case,

then, the concept of sensation straddles the division between physiol-

ogy and psychology, and thus, I suggest, obscures some very impor-

tant aspects of that division.

The focus of this paper will be on perceptual modalities, and their

relationship to sensation in that first, clear sense of physiological

response. The differences between modalities form some of our most

basic understandings of the structure of consciousness, and indeed the

very nature of consciousness. The traditional view of the nature of

perceptual modalities sees not only a strong continuity between the

physiological response to a stimulus and the resultant perception of it,

but a near identity between the two — an inextricable relationship

illustrated by the popularity of the second, more vague form of the

sensation-perception distinction. In this paper I will draw on both psy-

chological and neuroscientific research to undermine some of our

most fundamental intuitions concerning the relationship between sen-

sation and perception and thus to undermine the long-standing tradi-

tional account of perceptual modalities, an account which can trace its

lineage directly to Johannes Müller’s doctrine of ‘specific nerve ener-

gies’, put forward in 1826. In the place of this traditional account I

will argue for an enactive account of perceptual modality, one which

draws heavily on the work of Kevin O’Regan, Alva Noë and Erik

Myin amongst others (Myin & O’Regan, 2002; Noë, 2004; O’Regan

ENACTING MODALITIES 73

&; Noë, 2001a) but which offers a more coherent and more complete

story of the various elements of a modality.

The enactive approach to cognitive science has been knocking

around for a while now, but has thus far been largely relegated to the

domain of ‘low level’ cognition, the basic aspects of perception and

immediate bodily action. The account of modality that I will advance

later in this paper will provide grounds to reject a clear distinction

between lower and higher cognition, and attempt to show how an

enactive approach can equally and fruitfully be applied to our under-

standing of the richer and more complex forms of cognition.

The term ‘enactive’ has become something of a buzz word in the

recent Cognitive Science literature, and as such has developed a few

different meanings. In the present paper, I am applying the term in the

specific sense proposed by Varela, Thompson, & Rosch (1991), and

developed in subsequent works by several authors including Varela

(1997), Di Paolo (2005), Thompson (2007), Di Paolo et al. (in press)

and others. This approach is in many ways a continuing development

of the phenomenology of Merleau-Ponty, and the integration of some

of his insights with more recent developments in the dynamics of biol-

ogy and autonomous systems (see Varela, 1979; Weber & Varela,

2002; Thompson, 2007).

The emphasis on biological autonomy and the dynamic interaction

between such an autonomous system and its environment in the expla-

nation of cognition means that the enactive approach argues for a con-

tinuity between the basic processes that underlie life, adaptive

response to the world, and cognition. The mind is seen not as compris-

ing a set of distinct processes driving perception, cognition and

action, but a complex of skills which allow an autonomous agent to

maintain itself and achieve its goals in interaction with its environ-

ment. Perception, cognition and action are three facets of this single

process of adaptively coping with the world (what the enactive litera-

ture refers to as ‘sense-making’) rather than being distinguishable

links in a chain of processes that begin with ‘input’ at the sensory sur-

faces and end with ‘output’ at the muscles. Though the mind is driven

by the autonomy of the agent, all of its activities occur in engagement

with those aspects of the world around it that impinge upon it. The

description of either an agent or its environment will therefore always

perforce involve reference to the other – the cognitive agent and its

environment are inextricably entwined and an analysis must appreci-

ate not just one element or the other, but how the two interact and are

interrelated.

74 M. McGANN

Such a perspective makes the approach closely related to what I will

refer to as ‘dynamic sensorimotor’ accounts such as those of Susan

Hurley (1998; see also Hurley & Noë, 2003) and the theory of percep-

tion developed by O’Regan & Noë (2001a) and Noë (2004). Much of

this paper is a development of the implications of that theory. But the

enactive approach’s emphasis on the autonomy of the acting agent and

the emergence of cognition in the interaction between that agent’s

autonomous values and its environment, is not clearly laid out in a

dynamic sensorimotor view. Though the enactive approach used here

would involve a dynamic sensorimotor perspective, it is not clear that

the dynamic sensorimotor theories would adopt all aspects of an

enactive view.

The approach used here has a somewhat converse relationship with

the work of Natika Newton (1996), who strongly emphasises the

goals and values of cognitive agents and their essential (and often

overlooked) role in accounts of cognition. Newton, however, also

describes cognition as occurring in the embodied, sensorimotor repre-

sentations in the brain, whereas the enactive approach used in this

paper locates cognition only in the actual interaction between the

agent and its environment (for a more thorough exploration of the

‘where’of enaction, see Di Paolo, 2009). Such an enactive view, as we

shall see, provides some dramatically counter-intuitive implications

for even basic concepts of mind such as perceptual modality.

Perceptual Modalities

In traditional, and intuitive, ways of thinking, a perceptual modality is

a ‘mode of presentation’ of a particular stimulus. We might encounter

an object in many different ways, but one basic and simple aspect of

any perception will be the mode — visual, auditory, haptic etc. — in

which it is presented to us as perceivers.

The theory of modalities currently dominant in the cognitive sci-

ences is effectively that originally put forward by Johannes Müller on

‘specific nerve energies’. The essential idea is that sensory neurons

are responsive to particular forms of energy and it is this specificity in

neuronal response that gives a modality its character. The cells of the

retinae, for example, are specifically sensitive to light, and not, for

example, to temperature or sound, while the neurons of the cochlea

and ear are sensitive to the pressure waves of sound, but not to light.

This is a physiological explanation of perceptual modality that fits

well with our intuitions of clear distinct and basic modes of percep-

tion. Each modality, in this view, will have its own dedicated


anatomical organs — sight has the eyes, hearing the ears, taste the

tongue and so forth.

Modern neuroscience uses a version of this concept that is only

slightly modified, and is seen to have been ‘conclusively demon-

strated’ (Kandel et al., 1995, p. 371). This slight modification extends

the organs of interest from the sensory surfaces deep into the brain,

where we can find more anatomy particularly sensitive to and appar-

ently dedicated to dealing with, stimulation of a specific kind. These

neural organs appear to take sensory information in its raw form at the

sensory surfaces and pass it up to more complicated cross-modal pro-

cessing streams which are the medium of central, multi-modal cogni-

tion. It is processing in these more narrowly dedicated systems that is

believed to give a perception its specific modal character.

This standard view of modalities has more than a century and a half

of support and is pretty much unquestioned in current mainstream

Cognitive Science.

Just how many such modalities there are is not quite so clear,

though, even in the mainstream. Whatever the truth of the matter, it

would appear that we have more than the five traditional modalities.

Proprioception, the vestibular sense and kinaesthesia, for example,

extend beyond the typical conceptions of touch, and our perceptions

of texture, temperature and pain are all apparently underpinned by

separate neural systems. But this debate on the number of modalities

has not undermined the strong continuity between sensation and per-

ception inherent in the traditional view. In fact, the idea that the senses

can be distinguished and counted depends on the traditional model,

which make modalities modular — separated by separate organs and

neural bases, without cross-talk at least at the low levels of early

perceptual processing.

Research in both psychology and neuroscience, however, would

lead us to re-evaluate these basic elements of the traditional account of

modalities. In doing so, we find ourselves facing some important and

intriguing questions about the structure and form of consciousness.

Questioning Modality Modularity

Several cross-modality illusions indicate the presence of inter-modal-

ity influence. This begins to beg questions of the traditional view: if

the nerve energies are that specific, then there should be significant

insulation between modalities at least at the lowest levels. Modality

modularity should be a given. Probably the most commonly known

cross-modal illusion is the McGurk effect, first reported by McGurk

76 M. McGANN

& McDonald (1976). The McGurk effect is a phonological

misrecognition based on conflicting auditory and visual information.

Quite simply, while hearing one phoneme (such as ‘ba’) repeatedly

and watching someone mouth another (such as ‘ga’) at the same rate,

we can misperceive the sound as an intermediate phoneme (such as

‘da’). There are a number of further findings about the McGurk effect,

including that it occurs not only in adults but in children and that some

sounds are better than others for producing it. Because it is associated

with the articulation of phonemes, however, it is not the best evidence

for truly low level interaction between perceptual modalities. After

all, language is at least implied here, and thus the interaction is likely

to be the result of learning the speech sounds of our native tongues.

Such learned phenomena are usually taken to be higher level psycho-

logical phenomena, and will convince very few that we need to doubt

the kind of modularity of modalities that the specific nerve energies

theory tends to imply (though the McGurk effect has also been shown

in pre-linguistic children; Rosenblum et al., 1997). There are other

inter-modality interactions, however, some of which are more starkly

problematical for a traditional view. Shams et al. (2000; 2001) have

reported a cross-modal illusion they refer to as the ‘illusory flash

effect’. In the case of the illusory flash effect, a single brief flicker of a

visual stimulus is presented simultaneously (within 100ms) with two

auditory beeps. The result is the perception of two flickers of the

visual stimulus. Like many illusions, this effect is robust, resisting

practice and prior knowledge on the part of the perceiver. Violentyev

et al. (2005) describe a similar illusion induced by tactile stimuli

rather than auditory ones.

Shimojo & Shams (2001) review this phenomenon amongst a range

of others and conclude that the traditional modular view of sensory

modalities doesn’t hold up to proper inspection. Their conclusive title,

‘Sensory modalities are not separate modalities’, seems a bit strong to

our intuitions though — while we perceive the world as a rich weave

of sensations, visual, auditory, tactile and more, we do not perceive it

as a smear of indistinguishable modes of sensation. Such inter-modal

influence, however low level, may still not convince us that our expe-

rience of perceptual modalities is not simply dependent on the differ-

ent ways in which sensory information is transformed by our nervous

system as it is processed towards some multi-modal integration in the

brain. Striking work by the neuroscientist Walter Freeman, though,

makes a deeper and more profound challenge to a simplistic specific

nerve energies approach to modality. If Freeman is correct, then at the

very early stages of perceptual processing, the details of sensory


stimulation are lost, disrupting another aspect of the traditional view,

our intuitions about the continuity between sensation and perception.

Questioning Specific Physiological Bases

Neural dynamics, sensation and perception

Because in the traditional view the particular qualities of a modality

somehow arise from the specificity of nervous sensitivity, we should

expect unique neural pathways to maintain that specificity of sensitiv-

ity into the brain — the modern extension of Müller’s specific nerve

energies doctrine. The modalities of perception are therefore, under

the traditional view, entirely dependent on the character of sensation.

However, the work of Walter Freeman and his colleagues on the neu-

ral dynamics of perception cast some doubt on this possibility. In par-

ticular, Freeman has shown a Rubicon in perceptual processing, a

point where in the modalities of smell, touch, sight and hearing, the

sensory signal is completely lost, and perception determined not by

the pattern of stimulation at the sensory surface, but by its perturba-

tion of the inherent activity of the brain itself — it’s not just what the

sensory organs are doing, but what the brain is already doing, that is

involved in perception. Freeman’s work was conducted on rabbits,

and began with investigations into the neurophysiology of smell

(Freeman, 1991; 2000). Using internal measurement of the olfactory

bulb, Freeman showed that the activation of the bulb for similar stim-

uli in different reinforcement contexts was remarkably different. That

is, similar sensations did not necessarily produce similar activations

of the olfactory bulb. What is more, the patterns of activation for some

stimuli would change when other stimuli were given value through

reinforcement.

Figure 1. shows patterns derived from EEG readings of the bulb for

a rabbit before and after a new reinforcement contingency was intro-

duced the for the scent of amyl. Note particularly that the pattern asso-

ciated with air changes considerably after the change in reinforcement

condition despite the fact that no change in the value of the smell of air

was involved (the smell of air, in this case, is simply the background

smell of the rabbit’s cage). Freeman uses these and related findings to

argue that the patterns of response of the bulb to a given stimulus have

a lot more to do with the state of the bulb than they do the actual sen-

sory activity evoked by the stimulus. Because of the rich feedback

dynamics within the neurons of the olfactory bulb the activity on the

sensory surfaces cannot strongly determine the activity of the bulb.

Rather, sensory activity perturbs the continuously ongoing activity of

78 M. McGANN

the neurons. The patterns of activity in the bulb are largely the product

of its own activity and history. All sensation does is give it a nudge

across its own landscape of attractors. That perturbative nudge must

occur in a context of both recent activity of the bulb and the fact that

the landscape of its dynamical phase space is constantly changing.

The important point here is that what appears to have determined what

was smelled by the rabbits in Freeman’s studies was the rabbit’s own

history and the history of various reinforcement contingencies. The

sensory information per se plays a much attenuated role in forming

higher level neural patterns. What is processed by the perceptual

cortex is categorical, the meaning of the stimulus for the individual,

not the raw stimulus itself (Freeman, 1991). Perception does not

appear to be strongly determined by the specifics of the sensory level.


Figure 1. Surface EEG patterns for olfactory bulb responses to air and amyl

nitrate under different reinforcement conditions (adapted with permission

from Freeman & Schneider, 1982, ‘Changes in spatial patterns of rabbit

olfactory EEG with condiitoning to odors’, Psychophysiology, 19(1), pp.

44–56). Note that no change in reinforcement to air was involved, rather the

reinforcement of amyl alters the patterns of activation associated with air.

Freeman & Barrie (1994) generalised this point to the neural pro-

cessing of touch, audition and vision, once again in rabbits. What this

work shows is a Rubicon between sensation and perception which

means that wherever smell gets its odour, it is not from the activity on

the sensory surfaces of the nose. We may speak of ‘sensory modali-

ties’ but these are not the same modalities in which we perceive. This

is a profoundly counter-intuitive point, but it is one which we will see

is implied by the enactive approach to perception and which I am sug-

gesting is implied by the work of Walter Freeman and his colleagues.

The neurodynamics of sensation and perception undermine our basic

beliefs concerning the modalities of perception. The weak conception

of the sensation-perception distinction is challenged by these find-

ings, and deep problems open up for any account of perception which

relies heavily on an implicitly held continuity between the two. Note

that suggesting that the neural organs specific to different forms of

sensory stimulation are widely distributed, rather than anatomically

localised in the brain does nothing to attenuate the implications here.

What matters to the specific nerve energies view is that the neural

pathways are dedicated to the processing of the sensory information,

but Freeman’s studies show that that sensory information is irrevoca-

bly lost once it comes in contact with the complex, multiply connected

and autonomous activity that is already occuring in the brain.

What is more, that activity is not insulated from the broader interac-

tion between the animal and its environment. Nothing changes in the

amyl nitrate chemical itself during this research — it still interacts in

the same way with the olfactory receptors. But the implications of that

interaction, its value to the animal and its consequences for what the

animal is doing transforms the way the olfactory bulb responds not

just to that specific sensory signal, but to others too (as illustrated, the

background smell of the rabbit’s cage appears affected, despite not

being involved in a change in reinforcement value). This suggests that

what is going on is not some ‘top-down’ hypothesis of prediction

about what the signal might be, but a coordination of the rabbit’s

activity with the sensation. Perception is a complex of motivations

and on-going activities of the cognitive agent that is contextualised by

the animal’s needs, its behaviour and its history – it is not the output of

a progressive chain of processing, an assembly-line of sensations. Nor

is it a neutral prediction of what the sensation might be, given that the

nervous system’s responses alter not to changes in smells, but to

changes in their implication for the animal.

All this said, nor is perception arbitrary or unrelated to sensation.

Perception appears to involve coordinating with the world, not

80 M. McGANN

imposing any old interpretation upon it. We don’t just get to smell

what we want to, or even what we expect to. The question arises then,

if the character of perception is not determined by the sensory organs

being stimulated, what does determine it?

Freeman’s research suggests that somehow, it is not the eyes that

matter for vision, nor the nose for smell, but the right kinds of interac-

tion between an acting perceiver and the world. This is not to say that

normal vision does not depend on the eyes — that much is obvious —

but is to suggest that that even in the normal case vision is not just a

matter of what happens in the movement of neural activation upstream

from the retinae, and it is not necessarily dependent on optical input at

all. Evidence in support of such thinking, which I believe leaves the

traditional account of perceptual modalities wide open for assault by

the enactive approach, is the much quoted matter of sensory

substitution.

Sensory substitution

In work much cited within the enactive literature (e.g. (e.g . O’Regan

& Noë, 2001a,b; Noë, 2004; Hurley & Noë, 2003), neuropsychologist

Paul Bach-y-Rita (1972, see also 1984) has produced vision-like

experiences in both blind and normal participants, based entirely on

sensation on the skin. This remarkable effect is achieved using a

system referred to as TVSS (tactile-visual-substitution-system). An

array of vibrating contacts are placed on the skin (on the belly, back or

tongue) of the person. The activity of the array is controlled by a

camera which the person wears on their head. Bach-y-Rita (1972)

describes how, given a period of time actively exploring their environ-

ment with this system, participants (blind or blind-folded sighted peo-

ple) have reported experiencing depth, occlusion, basic object

recognition, looming and even one form of visual illusion (the water-

fall illusion, Bach-y-Rita, 1984). It is crucial that in the learning

phase, the participant have control over the camera — the sensation

alone is not enough. The person wearing the camera and vibrator

array must have the opportunity to integrate their tactile experiences

into a deliberate and on-going interaction with their environment.

Due to the limitations of skin sensitivity, the resolution of the vibra-

tor array is never very high (about 20x20; see Bach-y-Rita, 1983, for

discussion) and as a result the ‘vision’ it provides is weak indeed.

Nevertheless, the experience involved does appear to be visual (or at

least distal and spatial) in character, and is certainly not experienced

as tactile by the individuals in question. This despite the fact that they


can, if they wish, pay attention to the vibrations on their skin. They

generally don’t pay much attention after the training period, though,

and these sensations seem to be relegated to the same level of percep-

tion we normally have for the clothing or watch that we might be

wearing.

Neural dynamics work by Freeman and his colleagues, along with

such phenomena as TVSS, constitute a significant challenge to our

traditional conceptions of perceptual modalities. The question then

arises of how we might cope with this challenge. If the specific nerve

energies account of perceptual modalities is wrong, what kind of

account might we use to replace it? An enactive approach to percep-

tion, which would endorse such work as that of O’Regan & Noë

(2001a), Noë (2004), O’Regan et al. (2005) offers us a new means of

conceiving the differences between the modalities of perception.

The Enactive Approach to Perceptual Modalities

The basic conception of perception within the enactive approach is as

a sensitivity to the aspects of the world that have meaning for the

agent’s actions. At first blush, that seems like either a very tall order or

a rather vague promissory note. This general idea, however, makes

clear the fundamental and irreducible circularity of the relationship

between perception and action. We perceive, not as a broad hoovering

up of available information from the world, but in order to act. What

we perceive is determined as much by what we are trying to achieve as

what our sensory systems are capable of. We don’t just wait for the

world to come to us, nor do we passively accept information available

at the sensory surfaces.

A complete account of perception within the enactive approach is

beyond the scope of the present paper. We can briefly introduce our-

selves, though, to the aspects of such an approach that have a bearing

on our conception of modalities.

The dynamic sensorimotor theory of vision put forward by

O’Regan & Noë (2001a; see also Noë. 2004) is a strong foundation on

which to build a thoroughly enactive approach to perception. They

claim that to perceive is to exercise a mastery of the sensorimotor con-

tingencies of a given situation. Sensorimotor contingencies (SMCs)

are regularities in the interactions between our bodily movements and

our sensations. A very simple example is if you move your eyes to the

left, the pattern of stimulation on the retinae moves to the right.

Another is if you move toward an object, then the retinal stimulation

from points of texture on the object move outwards from the centre

82 M. McGANN

toward the periphery of the retinae. The important point here is that

the regularities that constitute these sensorimotor contingencies are

not simply part of the world, nor part of our sense organs, but arise

because both the world and our sense organs are relatively stable, and

therefore the interactions between the world and our sense organs will

have relatively stable characteristics. When we exercise a mastery of

these SMCs, when we can confidently and reliably guide our bodily

movements appropriately to perform actions in a given environment,

we are perceiving.1

In discussing sensorimotor contingencies, O’Regan & Noë (2001a)

distinguish between SMCs based on the object and those based on the

sensory apparatus. An example of an object-based visual SMC would

be that as a viewpoint moves around a mug, the handle appears, dis-

torts and disappears in characteristic ways. An example given of an

apparatus-based visual SMC is that as the eyeball moves a straight

line produces different forms of curves of stimulation on the retina

because of the shape of the eye and retina. O’Regan & Noë (2001a,

p. 946) identify apparatus-based SMCs as a significant original con-

tribution, something not present in previous action-focused accounts

of perception such as McKay’s and Gibson’s. The concept offers a

strong reminder of the importance of embodiment and bodily interac-

tion with the world.

Finally, O’Regan & Noë (2001a, p. 943) suggest that the difference

between sensation and perception is grounded in the difference

between object- and apparatus-based sensorimotor contingencies.

While it would appear (from evidence such as TVSS) that they are

correct in throwing into relief the role and the details of the physical

body for perception, the object-based versus apparatus-based SMCs

distinction doesn’t quite hold up to scrutiny. Take their example of the

distortion of stimulation on the retina given movements of the eyeball

— as the eyeball moves upward the stimulation on the retina from a

straight line in front of the person transforms from a straight line

(when the eye is focused directly on the line) to a curved one (when

the line is below the point of focus) because of the shape of the


[1] In more recent work, Noë (2004) prefers the phrase ‘knowledge of sensorimotor regulari-ties’. Reference to knowledge along with mastery is also made in the original O’Regan &Noë (2001a) paper. Precisely what kind of knowledge is involved, however, remainssomewhat unclear, and has been a source of criticism for the approach (e.g. Hutto, 2005;Rowlands, 2005). I have opted for the more skill-focused concept of ‘mastery’ as I find itthe more compelling account. The implications concerning perceptual modalities devel-oped later in the paper do not depend completely on this choice, however, and can also bedrawn out from a more knowledge-focused description of this dynamic sensorimotoraccount of perception.

eyeball. Those distortions of stimulation cannot be reliably contingent

without at least implicit reference to objects, or some external thing.

In the example given, the reference is an explicit one, to a straight line.

And there will always have to be such reference: while the idea of the

distinctiveness of apparatus-based versus object-based is sensori-

motor contingencies is a useful one to make clear the role of the details

of embodiment in perception, it should not be asked to do any real the-

oretical work. There is a distinction between sensation and percep-

tion, but it is not captured by the distinction between object- and

apparatus based SMCs. This does not cause immediate problems,

however, because O’Regan & Noë (2001a) do not really ask their def-

inition to do important theoretical work.

The sensorimotor aspects of the relationship between the agent and

their environment cannot be the whole story. That sensorimotor con-

tingencies enable perception is certainly consistent with the enactive

approach, but it lacks any reference to the endogenously driven activi-

ties of the agent — the valued, goal-oriented nature of an agent’s

actions. Perceiving is not sensorimotor contingencies alone, but the

exercise of their mastery. It is for this reason that O’Regan & Noë’s

view is considered a form of ‘skill theory’ of vision.

So how are modalities constituted within such an account?

O’Regan & Noë (2001a) claim that SMCs are governed by relatively

stable sets of laws, and that it is these more or less coherent sets of

laws that constitute a perceptual modality.2 As with the contingencies

themselves, the laws governing contingencies emerge because of the

details of our specific embodiment and the kinds of actions which our

environment enables. Some movements will affect the pattern of sen-

sation on the retinae, but have no effect on other sensations, e.g. a

movement of the head, which produces dramatic changes in retinal

stimulation but will have no effect on the feeling of a wine bottle in

our hands. Other movements will affect our sensations of touch (such

as moving our hands over that wine bottle), but have no effect on

vision. Below is a table, taken from an on-line draft of O’Regan et al.

(2005) which gives some examples of sensorimotor contingencies for

vision and hearing, and how these contingencies can offer an explana-

tion of the differences between the two modalities.

84 M. McGANN

[2] O’Regan & Noë (2001a) actually refer to the laws governing SMCs as constituting sen-sory modalities, but draw no explicit distinction between sensory and perceptual modali-ties. It seems clear, however, that if sensation is the transduction of specific kinds of ener-gies into neural activity then sensory modalities will be physiological and organ-specific –much closer to Müller’s view. O’Regan & Noë appear to acknowledge this in pointing outthat there are two different kinds of contingencies, apparatus-based contingencies andobject-based contingencies, as mentioned.

Action Seeing Hearing

Blink Big change No change

Moves eyes Translating flowfield No change

Turn head Some changes in flow Left/right ear phase and

amplitude difference

Move forward Expanding flowfield Increased amplitude in

both ears

Table 1. Some sensorimotor contingencies associated with seeing and

hearing (taken from a draft version of O’Regan et al., 2005, available on-

line at http://nivea.psycho.univ-paris5.fr/CONS+COG/CC_OREGAN.htm).

While the work of O’Regan, Noë and Myin challenges the intuitive

and traditional concept of perceptual modalities and offers us a foun-

dation for a properly enactive approach to modality, the enactive

approach demands a somewhat clearer emphasis on the agent’s valued

actions. O’Regan & Noë’s approach is not challenged directly by the

evidence presented earlier on cross-talk between modalities, and the

work on TVSS is directly invoked by them in support of their theory.

Their account of modalities emphasises the interaction between the

agent and their environment, perceiving as exploration of the world

rather than a passive reception of information about the world. Given

such a view, there can be no primitives of perception simply given by

physiology — everything is in the interaction. What is more, that

interaction is always going to involve some aspect of goal-directed

activity on the part of the perceiving agent. It is such activity that

drives the exploration of the world in the first place, and gives value to

the interaction, the results of that exploration. It is this aspect of the

process is not quite unpacked in the detail it needs in O’Regan &

Noë’s work (nor indeed, in Noë, 2004), and so how it impacts on the

way we should consider perceptual modalities from an enactive point

of view needs a little more exegesis. In particular, while O’Regan &

Noë (2001a) and O’Regan et al. (2005) discuss the concept of modali-

ties characerised by sensorimotor contingencies, they do not fully

explore some of the more significant implications of a skills-based

account.

Remember, again, that within the enactive approach perception,

cognition and action, rather than being separable or clearly


distinguishable processes, are more like different aspects of the one

process of adaptive coping in which a goal-directed agent is continu-

ally involved. Modalities are not atomic in nature, but a product of a

dynamic process which involves an embodied agent (with goals and

sensitivities) and a world.

Within the traditional view, which holds modalities as basic ‘modes

of presentation’, a perception is simply ‘presented’ to us as either

visual, gustatory, tactile and so on. All other aspects of the perception

(recognition of the object, interpretation of the event) are deemed to

involve some form of further, often inferential, cognitive operation.

The enactive approach, however, rails against any such stage-like

description of perception, and in doing so transforms (and indeed

multiplies) the modes of experience available to us. Cognition is not

added to perception after the fact, because it is inherent in the process

of perception itself, it is part of what continually initiates, drives and

structures the act of perceiving.

An enactive approach to perception thus maintains a strong distinc-

tion between sensation and perception. Perception, wrapped up as it is

in cognition, action, sense-making, is an activity embedded within,

contextualised by, value-driven intentional action. Sensation is on

aspect of an embodied agent’s interaction with the world, an important

part certainly, but not one with any veto or absolute authority as the

character of experience.

The demand that perception be understood as structured by the

intentional actions of the agent as well as by the sensorimotor contin-

gencies that arise from embodied interaction with the world means

that the character of our perceptions is never, and can never be, simply

visual, or auditory, or tactile. In the abstract perceptual task of a

chess-player looking at a chessboard, for example, the player is not

only engaged visually with the world, but also engaged ‘chessily’.

Our perception of the world is imbued with goal-orientation and skil-

ful appraisal, such that the ‘mode of presentation’ will be as much a

matter of the skills we are deploying at the time as it is a matter of the

dynamics of sensory stimulation involved. Describing the perception

of the board as visual without describing it as chessy would be as

incomplete a description of the perception as describing the board

without making mention of its visual characteristics.

All perception, then, is inherently multi-modal. Our more abstract

skills cannot be deployed without engaging the embodied skills of

sensorimotor activity, but those sensorimotor skills are not encapsu-

lated either, they are engaged (their use structured) in the context of

goal-directed action. And of course, any normal perception will

86 M. McGANN

involve a plethora of such skills — in looking at a chess board I will

also be guiding visuomotor behaviours, engaged in a social interac-

tion and be prepared to use a whole manner of other skills depending

on the details of my context. The different ‘modes’ of perception,

then, are not sharply separated, but develop and operate together, to

the point that they can have quite deep dependencies. Many of us with

poor vision will have had the experience of having to put on our

glasses in order to hear more clearly, the interaction between taste and

smell is celebrated, in a game of soccer being able see the opening and

available run is not something that comes without being a skilled

player, but once you’re good enough, you ‘just see it’.3 As a final

example, I offer this suggestion as a phenomenological exercise for

the reader. Close your eyes and spin yourself around (either while

standing or, more safely, in a swivel chair) until you feel that you are

becoming quite dizzy. Stop completely, then open your eyes and fixate

an object as best you can. Your head movements and retinal stimula-

tion will be almost identical to a situation in which your continuing

maintenance of and sense of your balance was not so disturbed, but

what is your perception like? If you are anything like me, you will find

evidence that normal ‘visual’ perception has a surprising dependence

on vestibular activity.

Sensory substitution research, where sensory dynamics are trans-

formed by augmenting or compensating technologies, also supports

this view of modality. Adaptation to the technology in question only

occurs when the person engages in active, goal-directed behaviour.

This is the case for TVSS (Bach-y-Rita, 1972), and also for various

vision-to-audition devices that have been developed, such as Meijer’s

(1992) The Voice, which transforms pixel information from a camera

into a collection of audible frequencies (see also Auvray et al., 2007,

for an analysis of objection recognition and localisation with the

device).

Adaptation to the technologies also appears to be activity-specific.

For example, participants using the Voice, were more likely to claim

that their experience more resembled vision for object localisation

tasks, but more resembled hearing for object recognition tasks

(Auvray et al., 2007). Auvray & Myin (2009) argue that such sensory

substitution research (they prefer the phrase ‘perceptual

augmentation’) implies that perceptual modalities are a not rigid set of


[3] I am not a skilled soccer player – my position on the team could best be described as ‘hand-icap’, in that I’m placed on the team with better players when we can’t make even num-bers. I’m sure that all of us have comparable experiences where it is clear that our friendscan ‘just see’ or ‘just hear’ something – it pops out to them – that is utterly obscure to us.

distinct categories but are more like a space of possibilities. Some

areas of this space are more populated than others (the ‘traditional’

modalities), but intermediate forms of perception are also possible.

Some participants in Auvray et al‘s work with the Voice suggested

that rather than experiencing something visual or auditory, their expe-

riences when localising objects with the device was closer to a ‘new

sense’. In the case of TVSS, there is a similar debate over whether the

new experience should be considered ‘visual’ per se (see for example,

Prinz’s, 2006, criticisms of Noë, 2004, but also O’Regan & Noë’s

2001, p.958, p.1013 discussion of TVSS as ‘quasi-vision’) but this is

only a concern if we have good reason to believe that modalities must

be modular and discrete, which it appears they are not.

An enactive approach to modalities does not, therefore, make

strong or exclusive distinctions between forms of perception. Rather,

modalities are areas of stability within this space of possibilities,

stabilities that form on the basis of multiple interacting constraints —

the sensitivities of the individual agent, their goals, their expertise.

Stability does not imply fixation or rigidity, however, and even these

enacted stabilities will be in continual development, as our sensitivi-

ties, goals and expertise change. Our experiences are stable because

this development is very slow relative to our on-going actions.

For many, this may all sound a bit too idiosyncratic. Fine, we might

train or develop our visual or auditory skills in various ways, but there

remains something fundamental, something basic, which we all share

and which characterises some aspects of our perception no matter

what our goals, intentions and activities. We may see in different ways

in different activities, but it is precisely what is similar across the

experience of those different activities that allows us to identify some-

thing like vision. Red is red is red, after all, and whether I’m seeing red

because I’m checking which bishop my opponent has ready to move

against my king, or because I’m judging whether it is the same colour

as the car I’m thinking of buying, or whether I’m deciding if I like it,

my visual perception is still of the same red.

For an enactive account too, vision is precisely a set of aspects of

our experiences that are similar across different intentional contexts,

but without those different contexts there would be nothing to identify

as visual. Identifying a perceptual modality is not basic or fundamen-

tal, but is something done in the very same way as other forms of per-

ceptual judgement — with figure against ground. The enactive

approach simply makes this interdependency in perception more

explicit and drives home the importance of always identifying both

aspects of it.

88 M. McGANN

But, a critic might continue, having identified a continuity or con-

sistency across contexts that we can label as the ‘visual’ aspects of

experience, can we not then state what it is that underlies that consis-

tency or continuity? The answer is that we cannot, not in the categori-

cal terms that such a critic would find satisfying. Perceptual

modalities are modes of interaction, fuzzy sets of activities structured

by skilful action, environmental affordance and biological sensitivity

and irreducible to any of those components. Visual perceptions can be

identified not by the organs or biology involved, but by the kinds of

actions that they make possible, the kinds of activities in which they

evoked. It is a characteristic not of the biology of the agent, but of the

interaction in which the agent is engaged. That means that any set of

skills developed to a similar extent, be they concerned with vision,

hearing, driving, chess or social interaction, with have equal claim to

being a modality of perception.

This emergent nature of modalities, though, is not necessarily a

problem, and does not mean that we cannot effectively identify, com-

municate and investigate them. We human beings do share many

forms of sensitivity and many basic motivations. What is more, our

childhoods are long apprenticeships in which the development of our

perceptual skills are shaped and channelled so that significant varia-

tions or idiosyncrasies in experience are unlikely and unusual. Our

social skills play a part in the deployment of our visual, haptic and

olfactory ones, and the community in which we exist hold norms of

activity and norms of description which constrain our experiences. A

delightful and useful exploration of the development and disciplining

of experiences which acknowledges the interplay between the object,

the acting perceiver and the community of perception is Barry Smith’s

(2007) discussion of wine-tasting. Smith examines how our experi-

ences are guided and encouraged by a community which both

demands and validates certain kinds of interactions with the objects of

that community’s intentions. Something might be objectively the case

about the object, but not discriminated without the community’s guid-

ance and endorsement, a case where the modalities of taste and smell

are transformed by the development of a new ‘wine’ modality sup-

ported by an interacting society of experts.

While shared biological sensitivities enable this sharing of interac-

tions, they do not determine it. The story of how modalities are formed

and stabilised over developmental time is one which involves many

more players than biological maturation. Examining this question in

the kind of depth it deserves is unfortunately beyond the scope of this

paper. Nevertheless, the fundamentally social nature of that


development is worth a brief comment. While our bodies provide very

basic modes of activity from birth, the most potent of these is social

activity, a form of interaction which will become the primary means

by which many of our perceptual capacities will be scaffolded, cali-

brated and put to use. Social interaction is a complex coordination of

activity between two agents (De Jaegher & Di Paolo, 2007), involving

embodied interaction as well as the mastery of a host of ‘social’ con-

tingencies. These contingencies are not only sensorimotor, but pri-

marily emotional or affective in character. Due to the pervasive nature

of social skill and social interaction, its foundational role in the forma-

tion of our minds and its primacy in our interacting with and learning

about the world, it deserves at least as much recognition as a modality

as any of those with an easily identifiable peripheral organ (see

McGann & De Jaegher, 2009, for the first steps in an enactive analysis

of social skill and social perception).

Such a claim points to a final potential criticism of the enactive

approach to modalities: the idea that despite all of these tortuous

accounts of perception, the sensory organ really is some kind of final

arbiter on the subject. Other ways of skilfully interacting with the

world may be perceptual modalities, but certain modalities (five that

we could name immediately) are special, because they have sensory

organs dedicated and unique to them, while other skills are parasitic

on those basic, genuinely sensory modes of exploration of the world.

But this is just the same organ-centric criticism addressed above and is

subject to the same response — all of that dedicated sensation gets us

nowhere without reference to the appetite for exploration and action

that has been emphasised above. Sensory organs may be vital, but no

perception depends on, nor can be explained by, a specific organ

alone. Yes, vision is obviously dependent on the eyes, but it is also

non-obviously dependent in the normal case on vestibular function,

proprioceptive function (eyeball movements, for example), audition

and who knows what else? We should certainly take care to ensure

that the obvious facts are accounted for, but there is no call to restrict

our accounts to the obvious facts. Furthermore, given the active nature

of perception, without an account of the intention, the skilled activity,

driving the interaction between sensory organ and environment, we

will never find meaning in the patter of stimulation at the sensory

surface.

If, following the same organ-centric logic, we deny that the case of

a skilled TVSS user is a case of vision, however attenuated (none of

the vision-specific nerves have been enervated after all), we would

still be very hard-pressed to defend the claim that the experience is

90 M. McGANN

one of touch. We can identify perceptual modalities by disciplining

our discourse and calibrating our experiences with one another over

developmental time and through social practice, but we will not be

able to draw sharp and conclusive boundaries between them.

Implications of Enactive Modalities

No theory of <Insert your favourite modality>

One of the most dramatic implications of this approach to modalities

is that while it may be possible to produce a general theory of percep-

tion (as one aspect of a general theory of mind), we will not ultimately

be able to produce a general theory of any particular perceptual

modality. There is no generic or pure vision, no generic or pure hear-

ing, but specific and task-dependent interactions which involve visual

and auditory modalities.

Most research in these various domains will actually be unaffected

by this, as applied questions dominate. Where research questions and

methods are developed within a particular context they will produce

perfectly useful conclusions and generalisations within that domain.

But if our ambitions are to produce broad theories of an entire way of

being conscious — a theory of seeing, or of hearing — then we are

bound to be disappointed. The context-dependent nature of percep-

tion is not an interesting quirk of the perceptual system, but a funda-

mental characteristic of its operation. If we have learned nothing else

in the past century and a half of empirical research into the mind and

consciousness, it is that context is not contextual.

Far from restricting the ways in which we study perception, though,

this description of modality opens up a wide array of new perceptual

questions and domains of application.

Extending our understanding of perception and enactive

cognition

If the modalities of perception are a matter of the skills through which

we interact with the world, then the range of modalities which human

beings experience is not just greater than the traditional ‘five’, but is

in fact innumerable. Of course, we have always known that expertise

transforms a person’s perceptions in appropriate contexts, but for the

main the research within Cognitive Psychology has treated that phe-

nomenon as a post-perceptual process of inferential pattern-matching.

Experts have tens of thousands of situations represented in memory in

some way, and those patterns can short-circuit complex computational

demands to provide immediate guidance for behavioural output.


Except, if the enactive approach is correct then no such pat-

tern-matching goes on. Rather, as Hubert Dreyfus (2002) has argued,

drawing on Merleau-Ponty’s (1962) phenomenology of perception

and Freeman’s neurodynamical work, experts exhibit transformed

interactions in their chosen fields. Rather than matching patterns or

considering outcomes their experience of the situation is structured

within their expertise, such that rather than the expert responding to an

interpretation of the situation, the situation directly evokes or invites a

particular response, one that is structured from its foundations by that

person’s expertise.

The distinction between ‘lower’ and ‘higher’ cognition is therefore

a misleading one, and we should do away with it. Perception and cog-

nition are not sequential links in a chain but are fused, inseparable and

complementary aspects of the process of adaptive coping by an agent

in its environment. Within the enactive literature, this process of adap-

tive coping is referred to as ‘sense making’ the production of meaning

in interaction (Varela, 1991; Weber & Varela, 2002; Thompson &

Stapleton, 2008). Cognition is not to be understood as a set of pro-

cesses which occur in the brain over increasingly more complicated

representations but is the on-going activity of an entire organism

carrying out its goals within an environment that is, like a fulcrum,

simultaneously constraining and enabling that activity. Any account

of cognition that hopes to do the phenomenon justice must thus

encompass the entire system of the biology of the agent (their embodi-

ment), their goals, expertise and the environment. The consciousness

of this system will not be easily partialled into simple or universal

components, neither perceptual modality nor cognitive module. Any

aspect of an agent’s awareness during a particular action will have to

be described and interpreted in light of the rest of the system during

that same activity.

Conclusion

Once we make a clear and consistent distinction between sensation

and perception, the nature and structure of our awareness of the world

around us becomes dramatically affected. Psychological and

neuroscientific research have made the concept of a set of dedicated,

modular systems for the processing of sensory-specific information

problematic. What seems at first an issue in need of innocuous refine-

ment in fact reveals some significant fault lines in the traditional view,

and opens a series of questions which I suggest are best answered by

recourse to an enactive approach to understanding the mind. Fully

grasping the implications of an enactive account of modalities, we can

92 M. McGANN

see that the enactive approach need not, indeed cannot, be restricted to

the traditionally ‘lower’ forms of cognition. Nor is consciousness ever

a bare or simple phenomenon. Our goal-directed actions and skilful

cognition infuse and form consciousness from its very foundations

and our understanding of the processes of skilful, on-line embodied

coping may be used to transform and guide our investigations into

traditionally abstract and ‘higher’ cognition.4

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94 M. McGANN

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